<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    // 能整除4且不能整除100或者能整除400

    var year = prompt()

    if (year % 4 === 0 && year % 100 != 0 || year % 400 === 0) {
      console.log('是闰年')
    } else {
      console.log('是平年')
    }

  </script>
</body>
</html>